OAKLAND -- The Alameda County District Attorney's Office has charged a legally blind Oakland man who was driving without a license with felony vehicular manslaughter for fatally hitting a retired San Francisco State professor in Berkeley in the spring.

Renowned psychologist and World War II veteran Joseph Luft, 98, was out on his daily walk on April 4 when he was hit by car in a crosswalk at Bancroft Way and Sacramento Street in Berkeley.

The driver, Robert Jack Gilchrist, who turns 57 on Friday, was charged on July 28 with two misdemeanors: vehicular manslaughter and driving without a license. The more serious charge was amended on Wednesday to felony vehicular manslaughter with gross negligence based on additional information obtained by the Alameda County District Attorney's Office, spokeswoman Teresa Drenick said. Drenick declined to give specifics.

Gilchrist was driving northbound on Sacramento Street at about 12:20 p.m. on April 4 when he struck Luft in the south Bancroft Way crosswalk, police said. Gilchrist told officers that he is legally blind. His driver license expired in 2000.

Luft, of Berkeley, died of his injuries later that day at Highland Hospital. He was a psychology professor at San Francisco State for decades and was named an emeritus professor in 1986. Luft was best known internationally for being the co-creator of the Johari window, an awareness exercise for people to determine how they perceive themselves and how they are perceived by others.

Gilchrist has been in Santa Rita Jail in lieu of $60,000 bail. He is scheduled to return to court to enter a plea on Aug. 14.